What middle name did J.K. Rowling adopt for her publishing name?

J.K. Rowling adopted Kathleen as the middle initial represented in her publishing name.

She was born Joanne Rowling and did not originally have a middle name. When Bloomsbury prepared the first Harry Potter book for publication, the publisher requested two initials because it was thought that a name without a clearly feminine first name might appeal more broadly to young male readers.

Rowling chose K in honor of her paternal grandmother, Kathleen Ada Bulgen. The result was the publishing name J.K. Rowling, with the K standing for Kathleen.

The author is often mistakenly described as having been born “Joanne Kathleen Rowling.” That is not her birth name; Kathleen was adopted for professional use. She has also used the name Robert Galbraith for her crime novels, but that is a separate pseudonym rather than an expansion of her initials.